Internal fixation with nails and plates is a well-known surgical procedure used in orthopaedics and traumatology for stabilization of proximal femoral fractures. This procedure is considered as a classical open major surgery carrying out several possibilities of serious complications. It was considered in the past that rigidity of the fracture fixation site is advantageous, therefore, many of the available internal fixation devices are built so as to eliminate all movements (except of sliding possible motion) at the fracture site. It is now generally accepted that some micro-movements at the fracture site are essential for better fracture healing and even for stimulating callus formation. However, this conception is not valid for intracapsular femoral neck fractures.
Internal fixation bears many disadvantages including the fact that the surgery is highly expensive and complex, which may be complicated by significant blood loss and infection. There is a lack of ability to perform post-operative re-fixation, the morbidity and mortality rates are high and as a consequence of the surgery, there is a prolonged hospitalization related to peri-operative complications. The death rates following internal fixation in cases of subcapital (intracapsular) fractures are intimidating: 3% in the hospital, 25% at one year and additional 40% at two years following the surgery. 30% experience avascular necrosis, 43% non-union and 50% experience peri-operative-postoperative local and systemic complications. The data is collected from Clinical Orthopaedics and Related Research 348:22–28, 1998; Clinical Orthopaedics and Related Research 399:119–128, 2002. These papers are incorporated herein as references; however, similar results were established and published in many other scientific reviewed publications. The consequences of intertrochanteric-pertrochanteric (extracapsular) fractures are no less frightening. 15% experience fixation failure, 10% dies at one year; 20% at two year, 20% complicated with infection, and 30% with mal-union. Similar consequences are found in subtrochanteric fractures.
External fixation using nails and screws connected to the femoral head, neck, and shaft through an external device provides the possibility to stabilize the fracture. This procedure is done using minimal invasive interventional surgery.
Clinical evidences clearly indicate that stabilization of a peritrochanteric femoral neck fracture by external fixation markedly reduces mortality, reduces the incidence of severe complications and improve fracture outcomes at the immediate postoperative time in comparison with the classical internal fixation. External fixation has other advantages such as decreased length of hospitalization and medical costs, reduces post-operative fracture pain, facilitates the access to the patient nursering care, reduces need for forced recumbency as well as risk of pressure sores, pulmonary embolism, pulmonary infection etc. External fixation is a safe and reliable method of achieving osseous stability in trochanteric femoral fractures. Generally, external fixation imparts versatility, ease to apply with minimal operative time, bleeding and tissue injury.
A percutaneous connection of a fractured upper part of the femur is disclosed in U.S. Pat. No. 5,429,641. Another example of an external trochanter splint is disclosed in U.S. Pat. No. 5,728,096. European patent application EP 0940124A1 teaches an external fixation device with changeable angle for trochanteric fractures. The devices that are disclosed herein as references as well as other similar devices for external fixation of trochanteric femoral fractures have many disadvantages and complications. One of the dangerous occurrences is the penetration of the neck screws into the acetabulum due to severe osteoporosis. Other disadvantages are hardware failure, the device is fixed in a lateral posterior bulging position that is uncomfortable, and there is an immense difficulty in the supine or sitting position of the patient.
It is a long felt need to provide an external device that eliminates the severe disadvantages of the available devices for external fixation of pentrochanteric fractures, which is one of the fixations that results in several complications.
As for the internal fixation, specially designed screws were developed, for example a screw member that is disclosed in PCT application published as WO00/67653, an intramedullary cavity nail disclosed in EP 0853923, or an anchor that is disclosed in U.S. patent application No. 2002/0143333. Another commercially available fixation is sold by Fixano s.a. by the commercial name osteosynthesis of unstable femoral neck fractures by D.S.S. system (double sliding screws).